The utilization in automotive vehicles of greases having extreme pressure, antiwear and high temperature properties has resulted in the publication by manufacturers of automotive vehicles of special specifications which must be satisfied by such greases. Thus, in the case of a grease to be used as a lubricant in constant velocity universal joints of the type used in front wheel drive vehicles, the grease must not only have extreme pressure and high temperature performance capabilities due to the proximity of the universal joints to the heat generating exhaust components of the vehicle, but, also, the grease must not attack or cause any appreciable deterioration of the elastomeric material of which the boots or seals used in the universal joints are fabricated. The attack or deterioration of the seals, which usually are formed of silicone based elastomers, may involve a change in hardness, tensile strength, elongation or volume of the seals any, or all of which changes can result in the breakdown, or at least the malfunctioning of the seals.